Please help - What to buy?

So I played Abyss SSF with an Oni Goroshi Wild Strike Assassin, had lots of fun up to map tier 10 when maps stopped dropping, so I transferred to buy them... and also a bunch of gear.

However, the char keeps dropping exalts left and right, and also with the ascendency reveal I'll probably have to keep playing him on standard because Assassin seems really buffed...

But right now I'm a bit at a loss what I should aim for on the market, so if some of you guys had a look at my gear and told me what you consider worst and what to replace it with, that would be hugely appreciated.
Themes of the char are Ele damage because Wild strike, all charges, though mainly frenzy, dodge and Lightning Coil phys mitigation.
There are some things that are maybe not otpimal but I've grown attached to them: the sword of course, also the Lightning Coil which I found on SSF and hope makes a nice match with the Wathcer's Eye PoL phys taken -> lightning. Then the whole + level Grace/PoL setup with The Vertex, although I could easily be convinced to drop that. Also thought about Atziri's step in that case.

Budget is around 4 ex at the moment.

Gear:

Finally, if someone wants to have alook at the whole char and tree and tell me what they think, that would of course also be very nice: www.poeurl.com/bLUf

I see what you're doing with your tree, you went right for all the life nodes. But you probably would have been better off with the Raider with that kind of build. Or maybe the Scion, then you could have gone Elemental Overload and Primeval Force, and still hit all the health nodes.

Assassin is for critical strike which you basically ignored in your skill tree. I think you'll do o.k if you're just trying to get through the T-14 and T-15 maps but your damage will be capped with your half-hearted critical strike build, probably not Shaper viable.

The only thing I can think of with your gear is to try a six link Belly of the Beast body armour. Then dual wield swords, I'd use Ahn's Might and one more powerful rare sword, highest DPS you can afford. Get Swagger, Twin Terrors, and Depth Perception in your tree. And get rid of Growh and Decay and Vigour, I don't really see how either of those fits your build. You need more critical strike for it to make sense.

I see what you're doing with your tree, you went right for all the life nodes. But you probably would have been better off with the Raider with that kind of build. Or maybe the Scion, then you could have gone Elemental Overload and Primeval Force, and still hit all the health nodes.

Assassin is for critical strike which you basically ignored in your skill tree. I think you'll do o.k if you're just trying to get through the T-14 and T-15 maps but your damage will be capped with your half-hearted critical strike build, probably not Shaper viable.

I actually was farming the sword with a ranger, a duelist and the shadow, and I was more interested in raider or duelist something but the sword happened to choose the shadow... yep, completely irrational. Also, I was really torn between trickster and assassin.

Which crit focused nodes would you have taken? I did take two clusters (Assassination/Fatal Blade), which are my only damage nodes besides the ele damage/penetration clusters. Heartseeker is weaker than those two, though I suppose I should take it as well, accepted. but what else?

Thanks also for the dual sword idea, but yeah, Oni Goroshi is the theme for this build, and I did play a dual sword gladiator (terrible probably, but made it til T14 and somehow survived much better than the assassin) last league.

OP - I see why did you take the Growth and decay passive (some regen to counter her embrace) but I would rather go through Will of blades and Fangs of the VIper.

It will save you 3 points yo can invest somewhere. You should take the Heart seeker passive and the jewel socket.

Thanks both of you guys! Not getting the jewel slot and Heartseeker was really itching me before, but I felt I had to care more for regen. I had resisted PoB thus far because I didn't like the idea of installing something but it did open my eyes on some issues:
- growth and decay is in fact ineffective. I had assumed that with a crit build with lots of fire damage I'd get some nice ignites which would also be boosted by the nodes, but it doesn't seem so. I haven't really understood the new ignite mechanics so yeah, it seems the crit multi doesn't help? whatever gonna drop that. I'm already dying quite a lot, but maybe if I kill things faster...
- I didn't like the Brutal Blade cluster because I'm not dual wielding so no block, but probably dumb to forego all that damage. That might mean tha again I won't get Heartseeker because the damage here is so much more, though it feels sad (I feel I can't drop Alira for 2 skill points right now, because losing the resists would hurt a lot reg gear... may have to revise that)
- also underestimated the Diamond flask. It's going to take the basalt flask spot probably. With all the degen I feel I need two life flasks, and with 40% phys converted to lightning I feel probably my biggest problem is elemental damage (well that and the degen)

Any significant upgrade will cost a lot.
You could drop one life flask and take Diamond flask to increase your effective crit chance (damage).

You can consider Atziri's Step boots (it will boost your spell damage mitigation) with nice enchant (leech, regen, penetration) in combination with good EVA helm with life, resist (or unique with life/resist good enchant) or just enchant your stuff.

You could get better rolled amulet with high life/ better flat phys/crit/res/accuracy and/or gloves with good speed/damage rolls

Surprise, I'm already in Standard (faster than I had thought), so now the budget is like maybe 10ex? No idea what I can get for that in Standard though... gonna focus on amulet, gloves, boots, in that order probably. Still mulling over The Vertex versus Atziri's Step